How to make an easy plaster shell "mother mold" for your DIY Silicone rubber mold. This 2-part shell will hold the soft rubber together so you can get a good casting from it without leaks or distortion. This rubber mold will be used to make hollow wax patterns that will be used in the "lost wax" process to make glass castings.
MATERIALS:
1. Bucket with room-temp water.
2. Plaster bandage cut into strips.
3. Scissors.
4. Releasable surface (silicone matt, pie-tin or similar).
5. Paste wax or petroleum jelly (for a release between layers).
6. Shop Towel/Rag.
NOTES:
1. Shell mold CANNOT have any undercuts or areas that it 'grabs' the
rubber mold, or it will NOT release.
2. Shell mold should follow seam line so that it will 'pinch' both halves
together to prevent leaks when casting molten wax.
3. Do NOT use a silicone gloves or a silicone mat during this process.
Silicone sticks to silicone, so this material will stick to those items.
4. Each half should be AT LEAST 3-4 layers of plaster cloth.
5. You MUST use a release-wax or vaseline-on the seam to keep both
halves from sticking together.
Post questions/comments below!
Demonstration by Professor Davin Ebanks, Kent State University.